Pregnant?

Good day, I’m new to this forum. I created an account because I feel like I might be pregnant.
* Just to add some context: I have a long history of stomach issues/nausea where stress is a possible cause. I also eat and drink pretty poorly.*
Well, I haven’t had any stomach/nausea issues for quite a while now. I’m currently in a stressful situation. I take the pill and always take an extra one if I have to vomit.
I’m now 3 weeks late. I have a lot of nausea, often in the morning, which returns later in the day. Lots of stomach pain/churning intestines. A strange feeling between my lower abdomen and my vagina, and I’m often tired. I pee quite often and then suddenly have a really urgent need to go.
So I was wondering which pregnancy test is the most reliable. The one from the doctor or from the supermarket/pharmacy or something like that.
I’m 19, so experiences from teenage moms are welcome, even though if I am pregnant, I won’t keep the baby because I can’t offer it a future right now.
Greetings, kip.